Hillman Imp family (1963 to 1976)

Why people buy one

• A light, well-packaged small car with an alloy overhead-camshaft engine, an all-synchromesh gearbox and independent suspension all round.
• Hagerty UK says the engine's reputation for unreliability is largely unfair, and that much of it came from mechanics who did not understand alloy engines at the time.
• The twin-carburettor Sport, Chamois Sport and Stiletto are lively, with Classic & Sports Car quoting about 90mph.
• Classics World calls a well-sorted car fun to drive and a good DIY project, with simple, accessible wiring.
• The Imp Club, founded in 1980, has a registrar for each model, a members' spares service and its own heritage certificates.

What to weigh up

• Hagerty UK says an Imp "can and will rust almost everywhere", and most rusty cars have already been scrapped, so survivors may hide old repairs.
• Neglected coolant corrodes the alloy engine and blocks the radiator, which leads to overheating and warped heads.
• Interior trim and fabric are very hard to find, so a car with missing or torn trim can be hard to put right.
• Twin carburettors, quad headlamps and Sport or Stiletto badges can be fitted to any Imp, so the car's papers and numbers must support a Sport or Stiletto claim.
• Badge-engineered twins share most parts, but the Singer, Sunbeam and Commer versions each have their own trim, so check which version the V5C describes. Imp-based kit and specialist cars (Clan, Davrian, Ginetta) are not covered here.
• Early Mk I cars had a pneumatic throttle and automatic choke that gave trouble when new; the Mk II replaced them with conventional parts (in 1965 according to Wikipedia, 1966 according to the Imp Club).

Where they rust

• The leading edge of the front bonnet, where imps.me.uk says corrosion starts and spreads quickly.
• Sills, which Classics World calls the most important structural area to check.
• Door bottoms, usually because the drain holes are blocked.
• The base of the rear screen pillars, where cracked paint at the seam hides rot.
• Rear wheel arches from the inside, and the trailing edges of the front arches where the wing meets the sill.
• The spare wheel well in the front compartment and the front suspension mounting underneath it.
• The floorpan, spring pans and rear spring mounting points; severe rot can let the spring push through the body.
• The box-section front swing axles, which imps.me.uk says cannot be welded and must be replaced if badly rusted.

Mechanical weak spots

• Coolant should be about 50 per cent antifreeze; weak coolant corrodes the alloy, sheds flakes into the radiator and causes overheating.
• Repeated head skimming after overheating can cause pinking. Blue smoke on a cold start usually means inlet valve seals; continuous smoke means worn rings or bores and a rebuild.
• The water pump should be renewed about every 25,000 miles. A temperature gauge reading very low may mean the thermostat has been removed.
• The all-synchro transaxle can have weak synchromesh on the lower gears, and a sloppy change often points to worn gear lever bushes. Clutch replacement means taking the engine out.
• Check the rubber doughnut couplings on the rear driveshafts for splits; a failed one can damage the radiator, exhaust and dampers.
• Steering is light rack-and-pinion; knocks or heaviness point to worn kingpins and bushes.
• Drum brakes are adequate for the weight; Sports and Stilettos have a servo and larger master cylinder. Brakes that bind can be caused by a blocked vent in the master cylinder cap. Front disc conversions are common.

At a Mathewsons viewing

• Compare the chassis number on the identification plate, and the engine number, with the V5C. Chassis numbers from July 1970 include a product code that identifies the model, so ask the Imp Club registrar for that model to confirm the number matches a claimed Sport or Stiletto.
• For a claimed Sport, Chamois Sport or Stiletto, ask for an Imp Club heritage certificate or a Rootes Archive Centre Trust record, which lists Imps from 1963 to 1976 and gives model, colour and build date where the record survives.
• Open the engine lid: look for twin Strombergs on a Sport model, check the coolant colour and level, and take off the oil filler cap to look for creamy emulsion.
• With a torch, look at the sills, the rear spring pans and the front swing axles, and lift the front compartment floor and the mats to check for rot and water.
• Check the interior trim is complete, then, if staff start the car, look for blue smoke from the tail and listen for knocks; do not assume it will be started.

Parts, specialists and clubs

Seen on Bangers & Cash

• Hillman Imp (Bangers & Cash series 13, episode 7, First shown March 2026)

Sources

• Buying guide: Hillman Imp (1963 to 1976) (Hagerty UK), 1 March 2023
• Hillman Imp buyer's guide (Classics World), 21 July 2025
• What to look for (imps.me.uk), accessed 14 October 2026
• Sunbeam Imp Sport (Classic & Sports Car), accessed 14 October 2026
• Sunbeam Imp Sport and Stiletto (Sunbeam Car Club, Australia), accessed 14 October 2026
• Later chassis and engine number coding (Tiger East/Alpine East), accessed 14 October 2026
• Heritage certificates (Rootes Archive Centre Trust), accessed 14 October 2026
• Hillman Imp (Wikipedia), accessed 14 October 2026